/*
 * Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the Classpath exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.btrace.aggregation;

import java.util.concurrent.atomic.AtomicInteger;

/**
 * Aggregation function for counting the number of values.
 * <p>
 * 
 * @author Christian Glencross
 */
class Count implements AggregationValue {

    AtomicInteger value = new AtomicInteger();

    @Override
    public void clear() {
        value.set(0);
    }

    public void add() {
        value.incrementAndGet();
    }

    @Override
    public void add(long delta) {
    	if (delta >= 0) {
    		value.incrementAndGet();
    	} else {
    		value.decrementAndGet();
    	}
    }

    @Override
    public long getValue() {
        return value.get();
    }

    @Override
    public Object getData() {
        return getValue();
    }
}
